1. Field of Invention
The multimission capability of TH-MM is related generally to surface ship and boats, and to subsurface vehicles which can operate successfully as a displacement and/or transplanar surface regimes, as well as a winged vehicle capable of subsurface operation though sustained downward hydrodynamic forces on its wings at design submerged operational speeds. The multimission also covers air drop into water directly into submerged operation, and amphibious water/beach operations.
2. Description of Related Art
Given the broad scope of the invention, a description of related art covers the following:
Subsurface Vessels
(a) Submarine is a vessel such as shown in FIG. 1A, supported on surface by buoyant forces with small buoyancy reserve on surface such as shaded area 3 in FIG. 1B. Descent and climb is controlled by adding or removing water ballast. Additional control is provided by external foils such as rear rudder in yaw, and forward horizontal foils 7 in pitch. the submarine is autonomous, capable of operating at the surface of the water in displacement mode but, in order to facilitate diving, its reserve buoyancy is minimal compared to surface ships and boats. Submarines can descend to large depths. Consequently, it must use circular structural cross-section such as in FIG. 1B to resist great compressive forces at depth. Submerged, but near surface it can ingest air by a retractable vertical tube called Schnorkel, unless nuclear powered (not requiring air for engine).
The ration of submarine weight to total displacement of its shape approaches 1 at surface and is substantially 1 when submerged.
The weight-to-drag ratio of a deeply submerged submarine can be high compared to surface ships at the same speed and weight, because when deeply submerged, it does not generate surface waves. Nuclear submarines have no practical restrictions on range and endurance. Their weight-to-drag ratio when operating at (or near) the surface, however, is not favorable due to great surface disturbance they create, as can be seen in FIG. 2 taken from published photographs of submarines at speed at the surface.
(b) Semi-submarine have been proposed as transport ships when a permanent submerged displacement volume and a surface-piercing strut for permanent fresh air breathing, allowing the use of internal combustion engines and increasing crew comfort. It is claimed to have favorable lift-to-drag ratio and favorable sea-keeping characteristics in certain sea conditions, compared to surface ships, for example as described in a paper by MIT's Professor Mandel's examining several novel ship types.
(c) Submersible is generally understood to be a subsurface vessel having a limited structural and operational subsurface capability. It is capable of surface actions such as firing guns and torpedoes. As designed in the past they had limited subsurface speed and range, for example, the earliest submersibles of the first World War.
(d) Swaths are multihulls with submerged displacement volume.
Subsurface Vessels
The present invention is also related in its surface operation to Transonic Hull and Transonic Hydrofield of patent application Ser. Nos. 08/814,418 and 08/814,417. It may also relate to art cited by Patent Office, and by applicant, in pursuit of application Ser. No. 08/814,418. However, the present application in its multimission bi-hydro substance, is not related to the above art.